bosh releases --jobs - shows available job names

Optional --jobs flag shows the available job template names in each release
version; if the director returns the "job_names" key in its GET /releases
endpoint.

Targeting director without API support:

```
   +-------+-----------+-------------+-------+
   | Name  | Versions  | Commit Hash | Jobs  |
   +-------+-----------+-------------+-------+
   | bosh  | 13.1-dev  | d380ee49+   | n/a   |
   |       | 13.2-dev  | d380ee49+   | n/a   |
   |       | 13.3-dev  | d380ee49+   | n/a   |
   |       | 13.4-dev  | ec1936b7+   | n/a   |
   |       | 13.5-dev* | d380ee49+   | n/a   |
   | redis | 1         | 59e77715+   | n/a   |
   +-------+-----------+-------------+-------+
```
Targeting director with API support:

```
+-------+----------+-------------+--------------------------------------------------------------------------------+
| Name  | Versions | Commit Hash | Jobs                                   
+-------+----------+-------------+--------------------------------------------------------------------------------+
| bosh  | 13.4-dev | ec1936b7+   | blobstore, director, health_monitor, nats, postgres, powerdns, redis, registry |
| redis | 1        | 59e77715+   | redis                                                                          |
+-------+----------+-------------+--------------------------------------------------------------------------------+
```